Last updated on February 20th, 2024

Can You Reuse Coffee in a French Press? Second Brew Insights

can you french press coffee twice?

SUMMARY: Whether it is to save money or cleaning time, many people wonder if you can reuse coffee in a French Press for multiple brews. While you technically can use coffee grounds twice in a French Press, I do not recommend it. The solubility of coffee is not like some teas that taste good with multiple steeps. If you brew a French Press multiple times with the same grounds, expect a weaker coffee with less flavor and caffeine. It can feel lame to throw out used grounds, but instead of brewing twice, consider repurposing used grounds for compost, as fertilizer, natural insect repellent, or in homemade candles.

I totally get the instinct behind wanting to squeeze a second cup from your French Press coffee grounds. Not only can it save money, but it also saves you the hassle of cleaning out the coffee press before brewing again. Plus it is less wasteful. However, can you actually French Press coffee twice and get decent results?

Yes, you technically can. However, in this article, I will explore the science behind coffee extraction and solubility in water, which are the main reasons reusing coffee grounds results in bad flavors and lower caffeine content.

Lastly, if you want to maximize the value of your coffee, we’ll cover some creative and practical ways you can use your spent coffee grounds!

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Can You Use French Press Grounds Twice?

It is not uncommon to steep the same tea multiple times, and the flavor often develops and gets better each time you steep it. So can you similarly refill a French Press and brew the same coffee grounds a second time? Yes, you technically can, and a sort of darkish liquid will result. However, because most of the coffee’s soluble compounds dissolved during the first brew, the second brew will be weak, bitter, and have much less caffeine.

If you use sweeteners and milk, these off-flavors may not be a huge downside. Plus, maybe a second cup with less caffeine is exactly what you want. So, I won’t say you cannot use French Press grounds a second time. However, as a coffee geek, I would advise against it.

Over Extraction

can you reuse coffee in a french press image

Extraction is the process of dissolving compounds within the coffee, including its caffeine content. And, while each coffee is unique, there is a middle range of extraction that leads to the best flavor.

Under extraction takes too little from the coffee, resulting in a weak brew with sour flavors and a quick finish.

Over-extraction means you took too much from the coffee, dominated by bitter flavors with a drying mouthfeel. As a full immersion brewing method, French Press coffee ideally extracts around 20 percent of the coffee during the first brew. So, no matter what you do, a second brew will extract the bitter and drying flavors of over-extraction.

Brewing French Press Twice: The Practicality of Second Brews

While I understand the inclination to extend the life of coffee grounds and the practicality of squeezing the most out of your beans, it’s crucial to set realistic expectations for the outcome of a second brew.

So, first and foremost, do not expect coffee to behave like tea, which often tastes good for multiple infusions. To understand why brewing coffee multiple times doesn’t work, we have to explore the science of coffee solubility.

Understanding Coffee Solubility and Brewing Basics

What does it mean when something is soluble? In short, solubility is when molecular solid compounds break their bonds and dissolve into water. The weak bonds of the solid—in this case, organic coffee material—disrupt the hydrogen bonds in water and form new bonds with the polar water molecules. So, as you brew coffee, you are dissolving compounds from the coffee material in this way.

As a general rule, coffee grounds can only dissolve up to about 30 percent of their compounds in hot water. Solubility increases with temperature, which is why an immersion like cold brew coffee extracts unique flavors.

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However, the ideal extraction does not dissolve everything from the coffee. The perfect extraction rate for coffee flavor is a precise window, typically between 18-22 percent of the coffee grounds’ total mass. And, as you just read, going beyond this can result in over-extraction.

So, if you achieve this extraction percentage on the first brew, you will squeeze a maximum of 10 percent additional extraction at the most. Plus, the remaining 10 percent will have more undesirable compounds that only come out of coffee once the more developed acidic flavors are already gone.

So while it may be tempting to double-dip with your coffee grounds in search of an extra cup, doing so moves you further away from that sweet spot of ideal extraction.

See Also: How To Choose The Best French Press Coffee Maker

Measuring Extraction Quality

Measuring extraction quality with taste

Besides tasting your brew, how can you measure coffee extraction? Is it just a subjective experience or are there objective ways to measure extraction quality?

Enter the refractometer, a tool that might sound more at home in a science lab than in your home coffee setup.

DiFluid R2 Extract Coffee TDS Refractometer for measuring coffee extraction

While it may seem excessive, coffee professionals and hard-core geeks use a refractometer to measure the concentration of coffee solubles in a brew. This is expressed through the measurement of total dissolved solids (TDS), measured by the subtle amount a beam of light bends as it passes through the liquid. The more it bends, the more dissolved solids are getting in the way.

Most home coffee enthusiasts do not need a refractometer, although some models are affordable. However, if I were to buy one, I would want it to be a more expensive model so I knew the results were precise and accurate.

Understanding Total Dissolved Solids

Now, you may ask, what exactly are these total dissolved solids? To put it simply, TDS are the organic compounds and mineral content dissolved in water during the brewing process. These solids are the essence of flavor in your coffee. Yes, coffee is mostly water. However, the small amount of dissolved coffee solids in your brew provides all of the flavor.

Coffee solubility is influenced by various factors including the grind size, water temperature, brew time, and, of course, the quality and freshness of the coffee itself.

The relationship between TDS and flavor is straightforward: the higher the percentage, the stronger and possibly more bitter the taste; the lower the TDS, the weaker the brew and the more sour it is. By using a refractometer, one can quickly determine the quality of the extraction, which helps professional baristas and enthusiasts alike fine-tune their brewing process for consistency and excellence in every cup. It is the best way to balance the subjective experience of taste with a more dependable scientific measurement.

So, needless to say, after considering the points above, re-brewing coffee in a French Press is unlikely to achieve that ideal TDS range. This does not mean you cannot brew a French Press twice, but that a second brew will never taste great or have the same caffeine levels.

See Also: Why Is My French Press Hard To Press: 3 Causes & Fixes

Alternative Uses for Used Coffee Grounds

If your goal for brewing a French Press twice was to avoid wasting coffee grounds, there are numerous creative and environmentally friendly ways to give your used coffee grounds a second life, including:

  • Compost
  • Fertilizer
  • Neutralizing odors
  • Insect repellent
  • DIY candles

Let’s start with composting—a favorite among gardeners. You can add used coffee grounds to compost bins as a source of nitrogen, an essential element that helps break down organic material, enriching the soil with nutrients. This enhanced soil can later be used in your garden, giving plants a healthy boost. Additionally, coffee grounds can serve directly as a fertilizer because they contain several crucial minerals for plant growth, such as nitrogen, calcium, potassium, iron, phosphorus, magnesium, and chromium.

If you’re dealing with pests in your garden, you can also use coffee grounds as a mulch that repels pests such as cats, slugs, and ants without harmful chemicals. Spent coffee can also attract beneficial creatures like earthworms.

Beyond the garden, one of my favorite uses I found online for used coffee grounds was homemade candles. If you enjoy do-it-yourself projects, imagine enjoying the cozy aroma of spent coffee grounds as the candle burns.

Reusing Coffee Grounds as a Candle


As a summary and review, let’s answer the most common questions people have about refilling a French Press for multiple brews.

Can you brew coffee grounds twice in a French press?

Yes, you can technically brew coffee grounds twice in a French press, but the second brew is generally weak and lacking in flavor. During the first extraction, coffee grounds give off most of their soluble flavor compounds and caffeine, making the remaining extractable material quite limited for a second brew.

Why does reusing coffee grounds produce a less flavorful cup?

Reusing coffee grounds produces a less flavorful cup because the majority of the flavor compounds and caffeine are extracted during the first brewing. The solubility of coffee grounds is around 30 percent, and once that is reached, there’s little left to extract, resulting in a subpar cup on the second brew.

Is there any caffeine left in used coffee grounds?

After the initial brewing, used coffee grounds do have some residual caffeine left, but it’s significantly less than what’s found in the first cup. The second extraction will likely result in a brew with very low caffeine content, making it somewhat unsatisfactory for those seeking its stimulating effects.

What can you do with used coffee grounds from a French press?

Used coffee grounds from a French press can be repurposed in several ways, such as for composting, as a natural fertilizer for plants, as an insect repellent, and even for making scented candles. These innovative uses help in reducing waste and can contribute to environmentally friendly practices.

Final Thoughts on Reusing French Press Coffee

While it is physically possible to rebrew coffee grounds in a French press, doing so greatly diminishes the flavor and caffeine content of the second cup. Go ahead and do it, especially if you will cover up the flavor with milk or sweeteners. However, I just wanted to make sure you knew what to expect, mostly that coffee does not extract like tea in this way!

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